Once that happens, code will resume execution at the "catch". If there is a breakpoint within a function that's evaluated as part of a "when", that breakpoint will suspend execution before any stack unwinding occurs; by contrast, a breakpoint at a "catch" will only suspend execution after all finally handlers have run.
6 Do I need to wrap try...catch in all functions? No, you don't, not unless you want to log it at every level for some reason. Just handle it at the top level. In an async function, promise rejections are exceptions (as you know, since you're using try / catch with them), and exceptions propagate through the async call tree until/unless they're ...
22 If there is a hierarchy of exceptions you can use the base class to catch all subclasses of exceptions. In the degenerate case you can catch all Java exceptions with:
I recommend using catch(Exception ex) when you plan to reuse the exception variable only, and catch (alone) in other cases. Just a matter of style for the second use case, but if personally find it more simple.
The third try-catch block is different. When it throws the exception, it will change the source and the stack trace, so that it will appear that the exception has been thrown from this method, from that very line throw e on the method containing that try-catch block.
This is my first time writing transaction, is it correct/best practice to have the TRY/CATCH block inside the transaction or should the transaction be inside the TRY block?
In the second scheme, if the promise p rejects, then the .catch() handler is called. If you return a normal value or a promise that eventually resolves from the .catch() handler (thus "handling" the error), then the promise chain switches to the resolved state and the .then() handler after the .catch() will be called. So that's difference #2.
The try/catch approach can't manage with common resource allocation/dealocation tasks such as sp_OACreate / sp_OADestroy, sp_xml_preparedocument / sp_xml_removedocument, session management in HTTP API and so on.
62 You cannot use try-catch statements to handle exceptions thrown asynchronously, as the function has "returned" before any exception is thrown. You should instead use the promise.then and promise.catch methods, which represent the asynchronous equivalent of the try-catch statement. (Or use the async/await syntax noted in @Edo's answer.)
